302 lines
10 KiB
Go
302 lines
10 KiB
Go
// Copyright (c) 2016-2017 The btcsuite developers
|
|
// Use of this source code is governed by an ISC
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package blockchain
|
|
|
|
import (
|
|
"math"
|
|
|
|
"github.com/btcsuite/btcd/chaincfg"
|
|
)
|
|
|
|
const (
|
|
// vbLegacyBlockVersion is the highest legacy block version before the
|
|
// version bits scheme became active.
|
|
vbLegacyBlockVersion = 4
|
|
|
|
// vbTopBits defines the bits to set in the version to signal that the
|
|
// version bits scheme is being used.
|
|
vbTopBits = 0x20000000
|
|
|
|
// vbTopMask is the bitmask to use to determine whether or not the
|
|
// version bits scheme is in use.
|
|
vbTopMask = 0xe0000000
|
|
|
|
// vbNumBits is the total number of bits available for use with the
|
|
// version bits scheme.
|
|
vbNumBits = 29
|
|
|
|
// unknownVerNumToCheck is the number of previous blocks to consider
|
|
// when checking for a threshold of unknown block versions for the
|
|
// purposes of warning the user.
|
|
unknownVerNumToCheck = 100
|
|
|
|
// unknownVerWarnNum is the threshold of previous blocks that have an
|
|
// unknown version to use for the purposes of warning the user.
|
|
unknownVerWarnNum = unknownVerNumToCheck / 2
|
|
)
|
|
|
|
// bitConditionChecker provides a thresholdConditionChecker which can be used to
|
|
// test whether or not a specific bit is set when it's not supposed to be
|
|
// according to the expected version based on the known deployments and the
|
|
// current state of the chain. This is useful for detecting and warning about
|
|
// unknown rule activations.
|
|
type bitConditionChecker struct {
|
|
bit uint32
|
|
chain *BlockChain
|
|
}
|
|
|
|
// Ensure the bitConditionChecker type implements the thresholdConditionChecker
|
|
// interface.
|
|
var _ thresholdConditionChecker = bitConditionChecker{}
|
|
|
|
// BeginTime returns the unix timestamp for the median block time after which
|
|
// voting on a rule change starts (at the next window).
|
|
//
|
|
// Since this implementation checks for unknown rules, it returns 0 so the rule
|
|
// is always treated as active.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c bitConditionChecker) BeginTime() uint64 {
|
|
return 0
|
|
}
|
|
|
|
// EndTime returns the unix timestamp for the median block time after which an
|
|
// attempted rule change fails if it has not already been locked in or
|
|
// activated.
|
|
//
|
|
// Since this implementation checks for unknown rules, it returns the maximum
|
|
// possible timestamp so the rule is always treated as active.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c bitConditionChecker) EndTime() uint64 {
|
|
return math.MaxUint64
|
|
}
|
|
|
|
// RuleChangeActivationThreshold is the number of blocks for which the condition
|
|
// must be true in order to lock in a rule change.
|
|
//
|
|
// This implementation returns the value defined by the chain params the checker
|
|
// is associated with.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c bitConditionChecker) RuleChangeActivationThreshold() uint32 {
|
|
return c.chain.chainParams.RuleChangeActivationThreshold
|
|
}
|
|
|
|
// MinerConfirmationWindow is the number of blocks in each threshold state
|
|
// retarget window.
|
|
//
|
|
// This implementation returns the value defined by the chain params the checker
|
|
// is associated with.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c bitConditionChecker) MinerConfirmationWindow() uint32 {
|
|
return c.chain.chainParams.MinerConfirmationWindow
|
|
}
|
|
|
|
// Condition returns true when the specific bit associated with the checker is
|
|
// set and it's not supposed to be according to the expected version based on
|
|
// the known deployments and the current state of the chain.
|
|
//
|
|
// This function MUST be called with the chain state lock held (for writes).
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c bitConditionChecker) Condition(node *blockNode) (bool, error) {
|
|
conditionMask := uint32(1) << c.bit
|
|
version := uint32(node.version)
|
|
if version&vbTopMask != vbTopBits {
|
|
return false, nil
|
|
}
|
|
if version&conditionMask == 0 {
|
|
return false, nil
|
|
}
|
|
|
|
expectedVersion, err := c.chain.calcNextBlockVersion(node.parent)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
return uint32(expectedVersion)&conditionMask == 0, nil
|
|
}
|
|
|
|
// deploymentChecker provides a thresholdConditionChecker which can be used to
|
|
// test a specific deployment rule. This is required for properly detecting
|
|
// and activating consensus rule changes.
|
|
type deploymentChecker struct {
|
|
deployment *chaincfg.ConsensusDeployment
|
|
chain *BlockChain
|
|
}
|
|
|
|
// Ensure the deploymentChecker type implements the thresholdConditionChecker
|
|
// interface.
|
|
var _ thresholdConditionChecker = deploymentChecker{}
|
|
|
|
// BeginTime returns the unix timestamp for the median block time after which
|
|
// voting on a rule change starts (at the next window).
|
|
//
|
|
// This implementation returns the value defined by the specific deployment the
|
|
// checker is associated with.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c deploymentChecker) BeginTime() uint64 {
|
|
return c.deployment.StartTime
|
|
}
|
|
|
|
// EndTime returns the unix timestamp for the median block time after which an
|
|
// attempted rule change fails if it has not already been locked in or
|
|
// activated.
|
|
//
|
|
// This implementation returns the value defined by the specific deployment the
|
|
// checker is associated with.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c deploymentChecker) EndTime() uint64 {
|
|
return c.deployment.ExpireTime
|
|
}
|
|
|
|
// RuleChangeActivationThreshold is the number of blocks for which the condition
|
|
// must be true in order to lock in a rule change.
|
|
//
|
|
// This implementation returns the value defined by the chain params the checker
|
|
// is associated with.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c deploymentChecker) RuleChangeActivationThreshold() uint32 {
|
|
return c.chain.chainParams.RuleChangeActivationThreshold
|
|
}
|
|
|
|
// MinerConfirmationWindow is the number of blocks in each threshold state
|
|
// retarget window.
|
|
//
|
|
// This implementation returns the value defined by the chain params the checker
|
|
// is associated with.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c deploymentChecker) MinerConfirmationWindow() uint32 {
|
|
return c.chain.chainParams.MinerConfirmationWindow
|
|
}
|
|
|
|
// Condition returns true when the specific bit defined by the deployment
|
|
// associated with the checker is set.
|
|
//
|
|
// This is part of the thresholdConditionChecker interface implementation.
|
|
func (c deploymentChecker) Condition(node *blockNode) (bool, error) {
|
|
conditionMask := uint32(1) << c.deployment.BitNumber
|
|
version := uint32(node.version)
|
|
return (version&vbTopMask == vbTopBits) && (version&conditionMask != 0),
|
|
nil
|
|
}
|
|
|
|
// calcNextBlockVersion calculates the expected version of the block after the
|
|
// passed previous block node based on the state of started and locked in
|
|
// rule change deployments.
|
|
//
|
|
// This function differs from the exported CalcNextBlockVersion in that the
|
|
// exported version uses the current best chain as the previous block node
|
|
// while this function accepts any block node.
|
|
//
|
|
// This function MUST be called with the chain state lock held (for writes).
|
|
func (b *BlockChain) calcNextBlockVersion(prevNode *blockNode) (int32, error) {
|
|
// Set the appropriate bits for each actively defined rule deployment
|
|
// that is either in the process of being voted on, or locked in for the
|
|
// activation at the next threshold window change.
|
|
expectedVersion := uint32(vbTopBits)
|
|
for id := 0; id < len(b.chainParams.Deployments); id++ {
|
|
deployment := &b.chainParams.Deployments[id]
|
|
cache := &b.deploymentCaches[id]
|
|
checker := deploymentChecker{deployment: deployment, chain: b}
|
|
state, err := b.thresholdState(prevNode, checker, cache)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
if state == ThresholdStarted || state == ThresholdLockedIn {
|
|
expectedVersion |= uint32(1) << deployment.BitNumber
|
|
}
|
|
}
|
|
return int32(expectedVersion), nil
|
|
}
|
|
|
|
// CalcNextBlockVersion calculates the expected version of the block after the
|
|
// end of the current best chain based on the state of started and locked in
|
|
// rule change deployments.
|
|
//
|
|
// This function is safe for concurrent access.
|
|
func (b *BlockChain) CalcNextBlockVersion() (int32, error) {
|
|
b.chainLock.Lock()
|
|
version, err := b.calcNextBlockVersion(b.bestChain.Tip())
|
|
b.chainLock.Unlock()
|
|
return version, err
|
|
}
|
|
|
|
// warnUnknownRuleActivations displays a warning when any unknown new rules are
|
|
// either about to activate or have been activated. This will only happen once
|
|
// when new rules have been activated and every block for those about to be
|
|
// activated.
|
|
//
|
|
// This function MUST be called with the chain state lock held (for writes)
|
|
func (b *BlockChain) warnUnknownRuleActivations(node *blockNode) error {
|
|
// Warn if any unknown new rules are either about to activate or have
|
|
// already been activated.
|
|
for bit := uint32(0); bit < vbNumBits; bit++ {
|
|
checker := bitConditionChecker{bit: bit, chain: b}
|
|
cache := &b.warningCaches[bit]
|
|
state, err := b.thresholdState(node.parent, checker, cache)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
switch state {
|
|
case ThresholdActive:
|
|
if !b.unknownRulesWarned {
|
|
log.Warnf("Unknown new rules activated (bit %d)",
|
|
bit)
|
|
b.unknownRulesWarned = true
|
|
}
|
|
|
|
case ThresholdLockedIn:
|
|
window := int32(checker.MinerConfirmationWindow())
|
|
activationHeight := window - (node.height % window)
|
|
log.Warnf("Unknown new rules are about to activate in "+
|
|
"%d blocks (bit %d)", activationHeight, bit)
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// warnUnknownVersions logs a warning if a high enough percentage of the last
|
|
// blocks have unexpected versions.
|
|
//
|
|
// This function MUST be called with the chain state lock held (for writes)
|
|
func (b *BlockChain) warnUnknownVersions(node *blockNode) error {
|
|
// Nothing to do if already warned.
|
|
if b.unknownVersionsWarned {
|
|
return nil
|
|
}
|
|
|
|
// Warn if enough previous blocks have unexpected versions.
|
|
numUpgraded := uint32(0)
|
|
for i := uint32(0); i < unknownVerNumToCheck && node != nil; i++ {
|
|
expectedVersion, err := b.calcNextBlockVersion(node.parent)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if expectedVersion > vbLegacyBlockVersion &&
|
|
(node.version & ^expectedVersion) != 0 {
|
|
|
|
numUpgraded++
|
|
}
|
|
|
|
node = node.parent
|
|
}
|
|
if numUpgraded > unknownVerWarnNum {
|
|
log.Warn("Unknown block versions are being mined, so new " +
|
|
"rules might be in effect. Are you running the " +
|
|
"latest version of the software?")
|
|
b.unknownVersionsWarned = true
|
|
}
|
|
|
|
return nil
|
|
}
|